Acquisitions - Narrative (Details) $ in Thousands				2 Months Ended	3 Months Ended								12 Months Ended			21 Months Ended
	May 03, 2017 USD ($)	Oct. 30, 2015 USD ($) shares	Jun. 30, 2014 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 USD ($) state client specialty	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) state client specialty	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2018 USD ($)	Dec. 01, 2016 USD ($)	Apr. 01, 2016 USD ($)
Business Acquisition [Line Items]
Consolidated net income					$ 28,256	$ 7,044	$ 5,220	$ (1,718)	$ (7,649)	$ 14,289	$ (17,095)	$ 19,186	$ 38,802	$ 8,731	$ 4,954
Release of remaining contingent liability													(44)	(769)	0
Goodwill					$ 117,589				79,648				117,589	79,648
Acquisition related costs													$ 1,975	78	$ 902
US Resources Healthcare, LLC
Business Acquisition [Line Items]
Contingent consideration, range of outcomes, high																		$ 4,500
Mediscan
Business Acquisition [Line Items]
Contingent consideration, range of outcomes, high		$ 7,000
Cash purchase price paid at closing		29,900
Cash consideration plus working capital estimate		28,000
Fair value of shares		$ 4,723
Fair value of shares (in shares) | shares		349,871
Net working capital adjustment		$ 503										$ 0
Release of escrow to seller	$ 5,000
Number of states | state					11								11
Number of clients (more than) | client					300								300
Number of specialties (more than) | specialty					70								70
Revenue since acquisition				$ 6,700
Net income since acquisition				300
Assets acquired		$ 17,200
Weighted average useful life of assets acquired		10 years
Goodwill		$ 14,338
Acquisition related costs				$ 700
Medical Staffing Network
Business Acquisition [Line Items]
Release of remaining contingent liability																$ 400
Contingent consideration liabilities																			$ 2,100
Potential Earnout, Attainment of Specific Performance Criteria in 2017 | US Resources Healthcare, LLC
Business Acquisition [Line Items]
Contingent consideration, range of outcomes, high																		1,000
Potential Earnout, Attainment of Specific Performance Criteria in 2017 | Mediscan
Business Acquisition [Line Items]
Contingent consideration, range of outcomes, high		3,500
Potential Earnout, Attainment of Specific Performance Criteria in 2018 | US Resources Healthcare, LLC
Business Acquisition [Line Items]
Contingent consideration, range of outcomes, high																		2,000
Potential Earnout, Attainment of Specific Performance Criteria in 2019 | US Resources Healthcare, LLC
Business Acquisition [Line Items]
Contingent consideration, range of outcomes, high																		$ 1,500
Acquisition-Related Contingent Consideration | US Resources Healthcare, LLC
Business Acquisition [Line Items]
Release of remaining contingent liability					$ 1,300
Assumed Additional Contingent Purchase Price Liabilities | US Resources Healthcare, LLC
Business Acquisition [Line Items]
Contingent consideration liabilities					200								$ 200
Assumed Additional Contingent Purchase Price Liabilities | Mediscan
Business Acquisition [Line Items]
Contingent consideration, range of outcomes, high					300				$ 300				300	$ 300
Contingent consideration liabilities					$ 5,200								5,200
Potential Earnout, Attainment of Specific Performance Criteria in 2016 | Mediscan
Business Acquisition [Line Items]
Contingent consideration, range of outcomes, high		3,500
Deferred Consideration Transferred | Medical Staffing Network
Business Acquisition [Line Items]
Contingent consideration liabilities			$ 2,500
Period of deferred consideration			21 months
Forecast | Assumed Additional Contingent Purchase Price Liabilities | Mediscan
Business Acquisition [Line Items]
Contingent consideration, range of outcomes, high																	$ 300
Acquisition-related Costs
Business Acquisition [Line Items]
Consolidated net income													$ 2,000
Trade names | Mediscan
Business Acquisition [Line Items]
Assets acquired		$ 3,200
Weighted average useful life of assets acquired		11 years
Customer relationships | Mediscan
Business Acquisition [Line Items]
Assets acquired		$ 5,200
Weighted average useful life of assets acquired		10 years
Databases | Mediscan
Business Acquisition [Line Items]
Assets acquired		$ 8,800
Weighted average useful life of assets acquired		10 years